Many industrial and commercial facilities produce superheated steam to drive turbines or perform other desired functions. Before the spent steam is returned to the boilers, the steam is often used throughout a facility as general process steam. Process steam can be used to heat the facility or can be used as a source of heat in various types of equipment such as thermocycle chambers, industrial drying machines and the like. In many applications, process steam is most efficiently utilized when the temperature of the steam is at, or near, the saturation temperature for its pressure. Desuperheating refers to the process of reducing the temperature of the superheated steam to a temperature near its saturation temperature.
An economical way to desuperheat steam is through the injection of water or steam atomized water, wherein relatively cool water or watervapor is directed into the steam header. The superheated steam expends energy evaporating and heating the injected water, as such the superheated steam is cooled in proportion to the temperature and volume of the fluid being injected. A disadvantage of desuperheating by water injection is that the atomizing orifice, used to create the discharging mist of either water or steam atomized water, requires frequent maintenance. As such, the atomizing orifice must be frequently replaced within the steam header.
Referring to FIG. 1, there is shown a conventional prior art desuperheater assembly 10 in conjunction with a steam header 12. The desuperheater assembly 10 is comprised of an elongated supply pipe 14 having a connecting flange 16 at one end and a spray nozzle 18 at the opposite end. The connecting flange 16 is coupled to a water supply line 20 that supplies water or steam atomized water through the supply pipe 14 to the spray nozzle 18. A steam header connecting flange 22 is radially disposed at a set position near the top of the supply pipe 14. The steam header connecting flange 22 is bolted to a side conduit flange 23 that leads into the steam header 12. The supply pipe 14 is dimensioned to extend through the side conduit flange 23 and support the spray nozzle 18 in the center of the steam header 12, as the steam header connecting flange 22 is bolted onto the side conduit flange 23.
The steam header connecting flange 22 is bolted to the side conduit flange 23 in a conventional manner. As such, to remove the desuperheater assembly 10 from the steam header 12, the flow of steam through the steam header 12 must be stopped and the pressure within the steam header 12 brought to ambient. At this point, the desuperheater assembly 10 can be unbolted and removed. The isolation of the steam header 12 is continued until a substitute desuperheater assembly 10 can be installed or until the needed repairs can be made to the original desuperheater assembly 10. In the prior art, steam headers are isolated either by bypassing the steam header through other pipes or stopping the production of steam throughout the entire system. When the effected steam header containing the desuperheater assembly is bypassed, the process steam is not properly cooled. This often causes operational problem in various systems that utilize the process steam and are designed to run on desuperheated steam. Additionally, the ability to bypass a desired steam header requires redundant piping, which greatly increases the cost and complexity of building the original steam system. Consequently, isolating the steam header that contains the desuperheater assembly is not always a viable option. In the prior art, the other alternative is to stop steam production or vent steam production, thereby stopping the flow of process steam through the facility. When the flow of process steam stops, production with the facility is often stopped. Consequently, maintenance to the desuperheater assemblies is typically passed over in favor of maintenance to the boilers, turbines or other complex production equipment. Furthermore, since maintenance to the desuperheater assemblies must wait for a disruption in steam production, maintenance to the desuperheater assemblies cannot be performed when desired. As such, the desuperheater assemblies often operate in need of maintenance, which reduces the overall efficiency of the steam system within the facility.
It is therefore an object of the present invention to provide a desuperheater assembly that can be removed from, or inserted within, a steam header without having to isolate the flow of steam through the steam header.